Urethanes of aromatic j acids



Patented Feb. 20, 1951 UBETHAN ES OF AROMATIC J ACIDS Vsevolod Tulagin, Phillipsburg, N. J., assignor to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application April 10, 1947, Serial No. 740,725

6 Claims. (01. ze -470') The present invention relates to urethanes of aryl J acids, to a method of producing the same, and more particularly to such compounds in which the esterifying group of the urethane radical is aliphatic.

J acid or 6-amino-l-hydroxynaphthalene-3-.

sulfonic acid is a well known dyestuff intermediate finding extensive use as a coupling component in the preparation of azo dyes. The same is true of the aromatic J acids, i. e., compounds in which the amino group of the J acid is mono-substituted by an aromatic radical. The aromatic J acids, however, suffer from the disadvantage that they are highly unstable and are therefore difficult to prepare and store in a chemically pure state. Furthermore, they are insoluble in acids and hence cannot be employed in reactions in an acid medium. These objections to the arcmatic J acids have prevented the extensive use of these highly desirable compounds in the preparation of dyestuffs.

J acid itself may be readily acylated to yield acyl derivatives thereof. The same is not true,

however, of the aromatic J acids, these being 1 very difficult to acylate. In fact, only on such derivative has been reported, namely, the formyl derivative characterized by Beilstein, volume 14, First Supplement, as fi-formyl-anilino-l-naphthol-3-sulfonic acid. According to Beilstein, this product is prepared by heating the parent phenyl J acid with 85% formic acid in the presence of sodium formate. The aforesaid compound has the following constitution:

som

properties far superior to the aryl J acids per se I or their formyl derivatives. Thus, the urethanes are easily prepared in a state of high chemical purity. They are stable, particularly to acids and alkalies, and may be kept for a long period of time without undergoing chemical decomposition. They are soluble in acids and accordingly may be employed in reactions involving an acid medium. Furthermore, when they are used as couplers in dye preparations, they yield dyes of the same general spectral character as those derived from the aryl J acids with the important exception that the dyeings obtained with the dyes prepared from the urethanes are superior in brightness to the dyeings obtained from the dyes-prepared from the aryl J acids.

Accordingly, an object of the present invention is urethanes of aromatic J acids.

A further object of the present invention is urethanes of aromatic J acids in which the esterifying group of the urethane radical is aliphatic.

A further object of the present invention is to provide derivatives of aryl J acids which are superior to the aryl J acids and their formyl derivatives from the standpoint of stability, solubility and ease of preparation.

A further object of the present invention is to provide a new class of couplers which yield dyes capable of producing dyeings of a superior brightness as compared with the dyeings obtained with dyes prepared from aryl J acids.

A further object of the present invention involves a method of preparing urethanes of aryl J acids.

Other and further important objects of the invention will be apparent as th description proceeds.

The urethanes of aromatic J acids contemplated herein have the following structural formula:

SOJH

methyl, ethyl, propyl, butyl, amyl, octyl, decyl, octadecyl and the like.

The urethanes are prepared by reacting an aromatic J acid with an alkyl chlorocarbonate in the presence of an acid binding agent at low temperatures while agitating the reaction mixture. As aromatic J acidsthere may be utilized phenyl J acid, *fi-naphthy-l J flacid, ;p-:anlSy1 J acid, -p-methylpheny1 J acid, p-chlorophenyl J acid, p-bromophenyl J acid, and. thelike. Suitable chlorocarbonates are methyl chlorocarbonate, ethyl chlorocarbonate, propyl chlorocarbonate, amyl chlorocarbonate, octyl chlorocarbonate, decyl chlorocarbonate, octadecyl 'chlorocarbonate, and the like. Suitable acid binding agents are inorganic alkalies such as sodium hydroxide, potassium hydroxide, sodium alcoholatasodium carbonate and the like; or organic bases suchas:

pyridine, quinoline and the like. Where the acid binding agent is inorganic, the reaction is generally carried out in an aqueous medium. However, where an organic binding agent such as pyridine is employed, it is preferable to carry out the reaction in the presence of an organic solvent for the aromatic J acid such asdimethyl formamide, diethyl formamide, formamide and the like. The reaction is efiected by agitation of 'theingredients at relatively low temperatures such 'as temperatures ranging from about 5 to C. The low temperatures are maintained during the'reaction by externally cooling the reaction mixture.

The urethanes, particularly those in which character R is a lower molecular weightv alkyl group, are'readily soluble in hot water and are not precipitated from such solutions 'by the addition of acid. The aqueous solutions of the urethanes are suitable for further condensation such as coupling reactions to produce am and other dyes.

The invention is further illustrated by thefollowing examples, in which the parts are by weight. It isto be understod, however, that the invention is not limited to these examples, the examples being illustrative only.

Example. I

Ethyl urethane of ,phenyl J acid .of .the .ror mula:

To a suspension of 37 parts of phenyl J acid (commercial product of 81% purity) in 200 parts of water are added 36 parts of 6 N sodium hydroxide solution. The mixture is stirred for 15 minutes and then treated with 12 parts of ethyl chlorocarbonate. The mass is rapidly agitated and maintained at approximately 5 C. by external cooling. After about *1'5 minutes, 17 parts of 6 N sodium hydroxide and ,12 parts of ethyl chlorocarbonate are added and the mixture is stirred for another 15 minutes. A third portion of sodium hydroxideand ethyl chlorocarbonate is then added as above. 7

An oil separates out whichgradually becomes 'crystallinezand is completely solid after anhour of stirring. This substance-is removed by-flltration, and dissolved in water. The solution is then 4 cooled to 30 C. and treated with salt solution to the point of incipient cloudiness. Upon cooling and seeding, the sodium salt of the ethyl urethane of phenyl J acid separates slowly as microscopic needles.

Example II Thepmcedureis thesameas in Example I excepting that p-anisyl J acidfis substituted for the phenyl J acid. The ethyl urethane of p-anisyl J acid is obtained as a highly insoluble sodium salt which separates from the reaction mixture as WElFfOlfIllGd'fltt plates.

Example III The procedure is the same as in Example I excepting that p-methyl phenyl J acid is used in place of the phenyl J acid in the above procedure. The ethyl urethane of p-methyl phenyl J acid is obtained as the sodium-salt in the form of fine needles.

Example I V The procedure ,is the same as in Example .I excepting that p-chlorophenyl 'J acid is utilized in pace of the phenyl J acid. The ethyl urethane of p-chlorophenyl .J acid is obtained as the sodiumsaltrin the form of microscopiccrystals.

Example V The procedureis the. same as inExarnple Lexcepting that butyl chlorocarbonate. is employed in lieu of the ethylchlorocarbonate. The product, obtained in the .iorm of the sodium salt, is butyl urethane of ,phenyl-J acid of the following formula:

Example 171' To a sclution .of 20 parts :of highly purified anhydrous pyridine salts'of phenyl J acid: in volumes of dimethyl formamide containing -8 parts I of pyridine 1 are added 175 :parts .of octamaterial .by filtration through a layer of .di-

atomaceousearth. The filtrate is evaporated to i drynesssand .the residue is extracted with *two .3005volume. portions of low boiling petroleum ether.

The .resulting, yellow solid is .dried and. dissolved in a minimum ,quantityof hot benzene. A.small.amountofjinsoluble material is removed .by filtration andflthe filtrate is maintained for .one-hournatifi. to .6 'C., whereupon the octadecyl urethane of phenyl J acid crystallizes out as the pyridine salt..in..the .form of plate-like crystals.

The product .is .cooled and dried. It may be iurthertpurified by recrystallization from alcohol and water.

The product has the following formula:

Various modifications of the invention will be apparent to those skilled in the art and therefore I do not intend to be limited in the patent granted except as required by the prior art and the appended claims.

I claim:

1. Compounds of the following structural formula:

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,731,643 Wagner et al Oct. 15, 1929 2,276,174 Fleischuser et a1. Mar. 10, 1942 FOREIGN PATENTS Number Country Date 152,679 Germany June 20, 1904 245,608 Germany Dec. 12, 1909 

1. COMPOUNDS OF THE FOLLOWING STRUCTURAL FORMULA: 